04BlackGmc

iTrader: (19)

Truck in sig on a WOT run, supposed to be tuned for mods, getting a retune soon..

Short fuel trim both banks 0
LFT bank 1 +6
LFT bank 2 +5
LFT AVG 0
Computer AFR 12.1
Timing 29-32
Front o2's 930 and 940.....
Why is it running so rich>? need a new tune?

nikon1999

iTrader: (22)

with tuning you could certainly dial the numbers in tighter, a little rich..but not crazy

04BlackGmc

iTrader: (19)

yea i guess thats what i get for mail order...live tune coming soon hopefully.
think im loosing much power by not having them close to 0?

nikon1999

iTrader: (22)

a few, but i dont think enough to feel a difference imo

wait4me

iTrader: (10)

LTFT are not used at Wot, so that wont matter. Also, with our tune, The o2 voltage will still be changing at wot, so you need a wide band to show the actual air fuel ratio. It will be at 12.7. That 12.2 is what the computer happened to be commanding, That dont mean actual. the wot o2 voltage that you are seeing isnt accurate becase they are moving up and down very quickly to tune itself at wot on purpose. You cant accuratly guess the airfuel ratio with the o2 voltage on our tunes.

If the pcm is seeing an air leak from the headers would be the only reason why it is running rich with the tune. That is because it sees fresh air so it will be adding fuel for no reason to make up for a fake lean condition.

Frost

iTrader: (45)

What? Positive LT trims can hang at WOT and offset commanded fueling....

wait4me

iTrader: (10)

My operating systems are modified to do different things.

wait4me

iTrader: (10)

Another thing is, Even if that was valid. the ltrim system is different values in every cell that the pcm is in. So that value could be at idle, which even on a non modified operating system would not effect a driving cell. 1-15.

SSpdDmon

iTrader: (10)

I'm with Jesse on this. You can't get an accurate WOT AFR from NBO2's. If you hook up a WBO2 and it reads rich, that's a different story.

04BlackGmc

iTrader: (19)

ok jesse i know you have tuned my pcm and im not ******* you, i know you can only get a mail order tune so accurate.

I have no headers leak. Installed them myself with copper gaskets i torqued the bolts down once and once again and ever since that they have never moved. no other leaks any where else also everything is sealed well from the headers to the ypipe to the cutout. no noise besides the regular noises you get from long tubes.

Its going on a wideband dyno for some numbers this weekend so ill see what it puts down and what the AFR is..

04BlackGmc

iTrader: (19)

So is there anything else that would cause this issue?

wait4me

iTrader: (10)

What issue?

04BlackGmc

iTrader: (19)

uhh the running rich issue,

for most the reason i dont think its a mech. running issue i just think maybe a tigher tune on the VE tables.

I had it live data logged and ran rich all across the table if i remember right.

wait4me

iTrader: (10)

Positive trims means the vehicle thinks it is running lean. so it added to bring it back to a 14.7 air fuel ratio. The Vehicle will be staying at a 14.7 any time it is in closed loop. That trim number just means that it had to add 5% of fuel to make it a 14.7 at that point.

04BlackGmc

iTrader: (19)

Yes i understand all that, i edited my post above. When a car/truck sees it running lean it will try and compensate for the issue by adding fuel on the trim, completly understood. My question is mine doing that.

wait4me

iTrader: (10)

It just means that your computer is doing its job and adjusting itself.

After your dyno and you get me a wot fuel ratio chart, I can force it to be exactly perfect to what ever you request.

wait4me

iTrader: (10)

Another thing to remember is, The Ve table does effect fuel, but it might not be the reason why a ltrim would be showing higher. MASS Air sensors, and o2 sensors also effect the ltrim number. So if the MOTORS VE has not been changed via camshaft or something that changes it ability to flow more air per rotation, then the Ve table should remain untouched. Anything within 5 % is fine. Normal things effect that number. Temperature, Even the octain/type of gas you use. That is why the system is there in place...

04BlackGmc

iTrader: (19)

Well everything is in good running order. o2's are both switching fine, mass have ben recently cleaned with CRC MAF cleaner. The only mods i have added since you last retuned it since the headers a new CAI and P&P TB and ive been having this issue before that. also it always rich like this.

Well if i decided to send this in after the dyno with the sheet i know another issue is off the line timing is still kinda low, could use a little more.

foff667

iTrader: (2)

sounds like you might wanna make some tuning software your next investment.

SSpdDmon

iTrader: (10)

If you're running 29-32* of timing at WOT, I doubt you need much more (if any at all) - especially with the stock cam. Also, if your NBO2's are anything like mine were with my Pacesetter headers, then .930-.940mV is about a 12.5:1 AFR. That's not very rich at all. It's almost perfect or right about where you want it (maybe a hair leaner). The problem is, you have no way of knowing for sure (as stated several times above) whether or not you are truly running rich like you think you are. Just because the PCM says it's commanding a 12:1 AFR doesn't mean that's what is coming out of the tailpipe. Get a wb readout and then worry about your setup. You might be slightly rich...but then again you might not be. No use in stiring up a frenzy until you have some reliable information. Fuel trims and a function-limited scanner won't cut it alone.